Humans reached Australia 65,000 years ago

New excavations of a rock shelter near Kakadu National Park indicate humans reached Australia at least 65,000 years ago - up to 18,000 years earlier than archaeologists previously thought.

Many scientists already accepted that the shelter, called Madjedbebe, was home to the earliest evidence of humans in Australia. But now, sophisticated dating of sediments at the site confirms it is one of the most significant cultural and archaeological sites in the world.

The site was last excavated nearly 30 years ago. At that time it was thought to be between 50,000 and 60,000 years old. But these dates had been disputed by some archaeologists. To settle the dispute, Dr Clarkson and colleagues returned to the site in 2012 and 2015 armed with more sophisticated technology and techniques.

Located 300 kilometres east of Darwin in Mirarr Country, the Madjedbebe rock shelter sits at the base of the Arnhem Land escarpment on a sandy plain. Dr Clarkson said the discoveries, published today in the journal Nature, demonstrated very strong cultural continuity at the site across thousands of years.

How do we know how old the Indigenous Madjedbebe rock shelter is?After surveying the area with ground penetrating radar, the team dug 20 1-by-1-metre pits down to a depth of more than 3 metres in previously unexcavated areas.As they dug down they discovered more than 11,000 artefacts embedded in three dense bands of sediments of different ages. There were also lower numbers of artefacts in the layers between these dense bands.

At the lowest level of the site they found:

The world's oldest-known ground-edge axe Australia's oldest-known grinding stone Flakes and points, probably used as spear tips Ochre and the world's oldest-known sheets of mica — a reflective mineral used to enhance paintings Evidence of a hearth